A cross-sectional study of temporomandibular joint coronal plane disk position: imaging reliability and clinical utility

Objectives. The aim of this study was to assess the reliability, frequency, and clinical significance of temporomandibular joint (TMJ) medial and lateral disk positions, observed in the coronal-oblique plane, to determine their importance in clinical diagnosis and for routine imaging. Study Design. This cross-sectional study involved secondary data analysis (clinical and imaging) of 401 participants of the TMJ Impact Study. We used the chi(2) statistic to evaluate the associations between coronal disk positions with (1) anterior disk displacements with reduction and without reduction; and (2) familiar TMJ pain resulting from excursive movements and palpation, range of motion, and joint sounds. Results. Anterior disk displacements of any type occurred in 67.5% of joints; in contrast, medial and lateral disk positions occurred in 16% and 24% of joints, respectively. Radiologist reliability was as follows: sagittal posterior band position: right kappa = 0.68, left kappa = 0.60, average 84% agreement; and medial or lateral disk position: right kappa = 0.36, left kappa = 0.32, average 70% agreement. Medial and lateral disk positions were associated with sagittal displacements (P < .001). However, there were no associations between medial and lateral disk positions and familiar pain, range of motion, and joint sounds. Conclusions. Coronal disk position does not contribute to clinical symptomatology or findings and currently lacks sufficient evidence to support its inclusion into standard TMJ imaging protocols or into a clinical diagnostic category.